Abstract in English:

PURPOSE: To evaluate the treatment outcome of severe peritonitis in rats submitted to permanent bilateral carotid occlusion (PBCO). METHODS: Sixteen Wistar rats (mean age of 8.5 months) with PBCO underwent autogenously fecal peritonitis, and were treated with moxifloxacin combined with dexamethasone, and followed-up for 45 days. Ten rats (mean age five months) without PBCO were used as a control group. The variables were expressed by their mean and standard error of the mean (SEM). p<0.05 was used for rejecting the null hypothesis. The study was approved by the Ethics Committee. RESULTS: There was a significant increase (p=0.0002) in the mortality and morbidity in older rats that underwent PBCO (study group). However, even among the survival rats presenting with severe residual abscesses both in the abdomen and thorax cavities, they present an almost normal life. CONCLUSIONS: The treatment of severe autogenously fecal peritonitis with intraperitoneal moxifloxacin combined with dexamethasone was very effective in young rats without permanent bilateral carotid occlusion. The treatment reached reasonable results in older rats with PBCO, even considering residual abscesses on abdomen and thorax. Older age was the greater risk factor for the outcome of the treatment of severe peritonitis. Sepsis remains a challenging situation, especially in elderly.

Abstract in English:

PURPOSE: To evaluate the feasibility of an experimental model of donors after cardiac death in remote ischemic preconditioning studies. METHODS: Twelve Landrace pigs were used as organ donors. They underwent cardiac arrest by coronary en block suture and interruption of ventilatory support. Haemodynamic data regarding the donor surgical protocol were evaluated. Studies variables included mean heart rate, systolic blood pressure, diastolic blood pressure, mean arterial pressure, central venous pressure and oxygen saturation and the time to death. RESULTS: Haemodynamic parameter indicated that the circulatory failure occurred after nine minutes of en block coronary suture and respiratory support interruption. The circulatory collapse occurred evenly across all groups. The heart rate and central venous pressure were statistically different between groups (p=0.023 and p=0.04), respectively. The remote preconditioning resulted in delayed time of death. CONCLUSIONS: The model is feasible, and was easily reproduced. The ischemic remote preconditioning tends to a slight increase in circulatory failure time.

Abstract in English:

PURPOSE: To evaluate the effect of a local application of simvastatin gel in repairing bone defects in the femurs of rabbits. METHODS: Two standard surgical cavities were created in the femoral epiphysis of 18 rabbits. In the simvastatin group (SG), the cavities were filled with a collagen sponge soaked in 0.5 ml of a simvastatin (1 mg) gel, and the cavities were covered with a biological membrane. The bone cavities in the second group (control group) were filled with a blood clot and covered with a biological membrane. On the 7th, 21st and 42nd days, six animals in each group were euthanized, and the femurs were subject to histological evaluation (vascularity, fibrosis, reactive bone formation, osteoblasts, and osteoclasts) and immunohistochemical (anti-VEGF and anti-osteocalcin) analysis. The results were analyzed using a Wilcoxon test (p<0.05). RESULTS: There were significant differences between the two groups: the SG had greater scores in comparison with the CG in terms of the degree of vascularity on the 7th and the 21st days, fibrosis on the 21st day, bone formation reaction on the 21st and the 42nd days and the number of osteoblasts and osteoclasts on the 42nd day. The immunohistochemical expression was also greater for osteocalcin and VEGF on the 7th, 21st and 42nd days. CONCLUSION: Surgical defects created in rabbit femurs were treated locally with simvastatin gel to stimulate bone repair, which promoted an ameliorative effect in the morphological and immunohistochemical markers of bone regeneration.

Abstract in English:

PURPOSE: To test the hypothesis that liver regeneration after partial hepatectomy can be influenced by the ileum. METHODS: Eighteen Wistar rats were distributed into groups of six animals: 1 - ileum resection+ hepatectomy 2/3; 2 - hepatectomy 2/3, and 3 - sham. Anesthesia with ketamine and xylazine i.p., aseptic technique, analgesia with meperidine (10mg/kg s.c.). On day 6, serum ALT, AST, alkaline phosphatase (AP) and albumin were measured. Liver regeneration and hepatocyte mitosis were quantified. Statistical analysis with ANOVA and Tukey tests, with significance p<0.05. RESULTS: In group hepatectomy+ileal resection, ALT, AST and AP were 180.6±24.9, 58.6±3.1 and 254.6±46.6 respectively. They were significantly higher than in the hepatectomy group, whose values were 126.0±16.5, 44.1±3.9 and 163.5±8.6, respectively (p<0.001). Albumin levels were not significantly different among groups. Liver regeneration in hepatectomy group (94.17%) was statistically higher (p<0.001) than in ileal resection+hepatectomy group (55.96%). In the latter group the mitosis of hepatocytes were significantly less frequent than in the hepatectomy group. CONCLUSION: The data confirm that the ileum positively influence on liver regeneration in rats undergoing hepatectomy.

Abstract in English:

PURPOSE: To evaluate morphological changes of the gastric stump and not resected stomach mucosa after the completion of truncal vagotomy. METHODS: Eighty male Wistar rats were divided into four groups: CT, TV, RY and RYTV. In CT group, abdominal viscera were manipulated and the abdominal cavity was closed, in TV vagal trunks were isolated and sectioned, in RY a partial Roux-en-Y gastrectomy was performed and in RYTV the vagal trunks were sectioned and a partial Roux-en-Y gastrectomy was performed. At the 54th week after surgery, the rats were euthanized. The findings were submitted to histological analyses. RESULTS: None macroscopic or histological alterations in groups TV and CT was observed. Specimens from RY and RYTV groups did not show alterations in the gastric stump mucosa. At the jejunal side of the gastroenterostomy we found shallow ulcerative lesions always single, well-defined and with variable diameter 3 to 6 mm, six times in the RY group and none in the RYTV group (RY>RYTV, p=0.008). Neoplastic or preneoplastic lesions were not diagnosed in all groups. CONCLUSION: Truncal vagotomy is a safe and non-carcinogenic method in not resected and partially resected stomach.

Abstract in English:

PURPOSE: To investigate the induction of neoplastic lesions under the action of ultraviolet B radiation (UVR-B) and dimethyl benzanthracene (DMBA). METHODS: Forty Wistar rats were assigned to four groups (ten animals each), according to the procedure: group A received UVR-B irradiation, group B received topic DMBA, group C, UVR-B+DMBA and group D as control, observed for ten weeks. In the tenth week they went through a skin biopsy and histopathological study. The average thickness of the epidermis was calculated and evaluated statistically. RESULTS: Macroscopic lesions in group B were more of inflammatory kind compared to group A. Group C presented more injuries with neoplastic features than the others (p<0.01). Histologically there was a significant increase in thickness of the epidermis of all groups compared to control, however the greatest thickness measures occurred in Group C (p<0.01). CONCLUSIONS: The population exposed to ultraviolet B radiation is subject to suffer skin lesions that can develop into cancer. The association with hydrocarbons as the dimethyl benzanthracene increases the possibility of malignancy. May not be clinically evident determine when a solar keratosis ends and when a CEC begins. For this reason, histological study associated with health education prompting the early and irreversible injury prevention is necessary.

Abstract in English:

PURPOSE: To evaluate modulatory effects of a hydroalcoholic extract of Brazilian red propolis (HERP) on dermal carcinogenesis using a murine model. METHODS: The HERP was used at concentrations of 10, 50 and 100 mg/kg (PROP10, PROP50 and PROP100, respectively) to modulate dermal carcinogenesis induced by the application of 9,10-dimetil-1,2-benzatraceno (DMBA) on the backs of animals. RESULTS: The chemical compounds identified in HERP included propyl gallate, catechin, epicatechin and formononetin. PROP100 treatment resulted in significantly decreased tumor multiplicity throughout the five weeks of tumor promotion (p<0.05), and this concentration also resulted in the highest frequency of verrucous tumors (p<0.05). All of the tumors that developed in DMBA-treated animals were regarded as squamous cell carcinomas and were either diagnosed as non-invasive verrucous carcinomas or invasive squamous cell carcinomas (SCCs). The average score for malignancy was significantly lower in the PROP100-treated group than the non-treated group (p<0.05), but there was no difference between the other groups (p>0.05). CONCLUSION: The oral administration of hydroalcoholic extract of Brazilian red propolis at a dose of 100 mg/kg had a significant modulatory effect on the formation, differentiation and progression of chemically induced squamous cell carcinoma in a murine experimental model.

Abstract in English:

PURPOSE: To investigate the effects of alloxan diabetes on the abdominal wall healing of rats undergoing laparotomy. METHODS: Ninety-six male Wistar rats weighing between 200 and 300 grams, divided into two groups: non-diabetic group (G1) and another with untreated diabetes (G2). Three months after diabetes induction, the animals underwent a 5cm-long- laparotomy and 5.0 nylon monofilament suture. After the surgery, 12 animals from each group were euthanized on days 4, 14, 21 and 30 corresponding to the moments M1, M2, M3 and M4. In each moment a fragment of the abdominal wall containing the scar was removed for tensile strength measurement, histological and morphometric study. Clinical and biochemical parameters were also analyzed. RESULTS: G2 animals showed parameters compatible with severe diabetes and decreased plasma levels of insulin. The tensile strength in G2 was significantly smaller in M2 and M4, with a tendency to fall in the other two. Through light microscope, diabetic animals showed more difficulty to increase collagen density and contraction. G2 animals showed high cellularity of fibroblasts in later healing moments, with collagen thinning in M2 and M4. CONCLUSION: The abdominal wound healing in untreated diabetic animals was altered and led to a higher incidence of dehiscence and infections.

Abstract in English:

PURPOSE: To analyze the effects of application of 1% and 3% insulin-like growth factor I (IGF-1) cream on the process of wound healing in induced skin lesions in diabetic and non-diabetic rats and evaluate its effect on expression of myofibroblasts. METHODS: Ninety-six Wistar adult male rats were divided into six groups, with 16 rats in each group, as follows: group 1: non-diabetic, untreated; group 2: non-diabetic, treated with 1% IGF-1 cream; group 3: non-diabetic, treated with 3% IGF-1 cream; group 4: diabetic, untreated; group 5: diabetic, treated with 1% IGF-1 cream; and group 6: diabetic, treated with 3% IGF-1 cream. In groups 4, 5, and 6, diabetes was induced by intravenous injection of alloxan. After diabetes had been induced, animals were mantained for 3 months. The experimental procedure consisted of the creation of a circular incision of 0.9 mm in diameter using a metal punch. Following this, wounds were treated daily according to the assigned treatment regimen. Groups 2 and 5 were treated with 1% IGF-1 cream, groups 3 and 6 with 3% IGF-1 cream, and groups 1 and 4 and the untreated groups with 0.9% saline solution. From each group, samples from 4 rats were taken at three, seven, 14, and 21 days after the injury. Samples were fixed in 10% formalin to prepare slides for histological analysis. Slides stained with hematoxylin-eosin (H&E) and Masson were observed vascular proliferation, mononuclear cells, polymorphonuclear cells, fibroblast proliferation, re-epithelialization, and collagen fibers. This study analyzed the expression of α-smooth muscle actin using specific antibodies to correlate the temporal expression of α-smooth muscle-specific actin (α-SM actin), a molecular marker for myofibroblast transformation. RESULTS: Macroscopic observation of wounds showed a more rapid re-epithelialization of wounds treated with IGF. Regarding acute inflammatory reactions, the results of the analysis of vascular proliferation and polymorphonuclear and mononuclear cells showed no statistically significant differences in any of the periods studied (according to the results of a Mann-Whitney test). The initial immunohistochemical analysis of tissue samples conducted to compare the expression of α-smooth muscle actin between groups showed a relevant response in the expression of myofibroblasts. Data were analyzed using ANOVA and were found to be statistically significant. CONCLUSION: The topical application of 1% and 3% IGF-1 creams increases the expression of myofibroblasts in the process of wound healing in rats.

Abstract in English:

PURPOSE: To propose a simulation-based ultrasound-guided central venous cannulation skills' training program, during residency. METHODS: This study describes the strategies for learning the ultrasound-guided central venous cannulation on low-fidelity bench models. The preparation of bench models, educational goals, processes of skill acquisition, feedback and evaluation methods were also outlined. The training program was based on key references to the subject. RESULTS: It was formulated a simulation-based ultrasound-guided central venous cannulation teaching program on low-fidelity bench models. CONCLUSION: A simulation-based inexpensive, low-stress, no-risk learning program on low-fidelity bench models was proposed to facilitate acquisition of ultrasound-guided central venous cannulation skills by residents-in-training before exposure to the living patient.